微信支付退款的官方文档
https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=9_4
导入证书
微信退款是需要证书的
https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=4_3
以在windows为例，解压之后的文件
双击.p12结尾的文件，导入证书，会要求输入密码，密码就是商户ID，注意一定要是在自己的商户平台上下载的证书，不然会提示密码错误。
导入成功
Java代码
封装了一个RefundVo对象，字段设定根据官方文档
public class RefundVo {
private String appid;
private String mchId;
private String deviceInfo;
private String nonceStr;
private String sign;
private String signType;
private String transactionId;
private String outTradeNo;
private String outRefundNo;
private int totalFee;
private int refundFee;
private String refundFeeType;
private String opUserId;
private String refundAccount;
//省略get set方法
}
设置各个参数
String key = "xxxxxxx";
RefundVo vo = new RefundVo();
vo.setOutTradeNo("2016006092770333");//商户订单号（微信订单号二选一即可）
vo.setAppid("appid");
vo.setMchId("mchid");
vo.setOutRefundNo("2016006092770333");//某付款的定单号
vo.setTotalFee(1);//订单金额
vo.setRefundFee(1);退款金额
vo.setOpUserId("1410417402");//默认商户号
String certificatePath = "E:/工作/cert/apiclient_cert.p12";//证书的绝对路径
refund（key ，vo,certificatePath ）;
封装退款的结果
public class RefundResult {
private String returnCode;
private String returnMsg;
private String resultCode;
private String errCode;
private String errCodeDes;
private String appid;
private String mchId;
private String deviceInfo;
private String nonceStr;
private String sign;
private String transactionId;
private String outTradeNo;
private String outRefundNo;
private String refundId;
/**
* ORIGINAL—原路退款
* BALANCE—退回到余额
*/
private String refundChannel;
/**
* 申请退款金额
*/
private int refundFee;
/**
* 退款金额
*/
private int settlementRefundFee;
private int totalFee;
private int settlementTotalFee;
private String feeType;
private int cashFee;
private int cashRefundFee;
//省略set get方法
}
退款的方法
public RefundResult refund(String key,RefundVo vo,String certificatePath){
RefundResult refundResult = new RefundResult();
vo.setNonceStr(RandomUtil.wechatRandomString());//设置随机字符串
vo.setSign(new RefundBuilder().build(vo));//设置签名
check(vo);//检查参数
//将参数放入Map中
Map params=new RefundBuilder().getParams(vo);
//转成Xml形式的String
String xml=XmlParseUtils.assembleXml(params);
/**
wx2421b1c4370ec43b
10000100
6cefdb308e1e2e8aabd48cf79e546a02
10000100
1415701182
1415757673
1
1
FE56DD4AA85C0EECA82C35595A69E153
**/
//调用微信接口
String result = HttpClientUtils.executeBySslPost(refundURL,xml,vo.getCertificatePath(),vo.getRefundVo().getMchId());//发送http请求
//接收xml解析的结果
Map map = new HashMap();
//返回结果为xml形式，转成map然后封装成refundResult即可
map = XmlParseUtils.parseXml(result);
refundResult = new RefundResultBuilder().build(map);
}
参数检查
private void check(RefundVo vo){
if (VerifyUtils.isEmpty(vo.getAppid())) {
throw new PayException("申请退款参数为空——appid");
}
if (VerifyUtils.isEmpty(vo.getMchId())) {
throw new PayException("申请退款参数为空——mch_id");
}
if (VerifyUtils.isEmpty(vo.getNonceStr())) {
throw new PayException("申请退款参数为空——nonce_str");
}
if (VerifyUtils.isEmpty(vo.getSign())) {
throw new PayException("申请退款参数为空——sign");
}
if (VerifyUtils.isEmpty(vo.getTransactionId()) && VerifyUtils.isEmpty(vo.getOutTradeNo())) {
throw new PayException("申请退款参数为空——transaction_id或者out_trade_no");
}
if (VerifyUtils.isEmpty(vo.getOutRefundNo())) {
throw new PayException("申请退款参数为空——out_refund_no");
}
if (VerifyUtils.isEmpty(vo.getTotalFee())) {
throw new PayException("申请退款参数为空——total_fee");
}
if (VerifyUtils.isEmpty(vo.getRefundFee())) {
throw new PayException("申请退款参数为空——refund_fee");
}
if (VerifyUtils.isEmpty(vo.getOpUserId())) {
throw new PayException("申请退款参数为空——op_user_id");
}
}
Map构建
public class RefundBuilder extends SignBuilder {
@Override
public Map getParams(Refund vo) {
Map params = new HashMap();
if(VerifyUtils.isNotEmpty(vo.getAppid())){
params.put("appid",vo.getAppid());
}
if (VerifyUtils.isNotEmpty(vo.getMchId())) {
params.put("mch_id", vo.getMchId());
}
if (VerifyUtils.isNotEmpty(vo.getDeviceInfo())) {
params.put("device_info", vo.getDeviceInfo());
}
if(VerifyUtils.isNotEmpty(vo.getNonceStr())){
params.put("nonce_str",vo.getNonceStr());
}
if (VerifyUtils.isNotEmpty(vo.getSign())) {
params.put("sign", vo.getSign());
}
if (VerifyUtils.isNotEmpty(vo.getSignType())) {
params.put("sign_type", vo.getSignType());
}
if (VerifyUtils.isNotEmpty(vo.getTransactionId())) {
params.put("transaction_id", vo.getTransactionId());
}
if (VerifyUtils.isNotEmpty(vo.getOutTradeNo())) {
params.put("out_trade_no", vo.getOutTradeNo());
}
if (VerifyUtils.isNotEmpty(vo.getOutRefundNo())) {
params.put("out_refund_no", vo.getOutRefundNo());
}
if (VerifyUtils.isNotEmpty(vo.getTotalFee())) {
params.put("total_fee",Integer.toString(vo.getTotalFee()));
}
if (VerifyUtils.isNotEmpty(vo.getRefundFee())) {
params.put("refund_fee", Integer.toString(vo.getRefundFee()));
}
if (VerifyUtils.isNotEmpty(vo.getRefundFeeType())) {
params.put("refund_fee_type",vo.getRefundFeeType());
}
if (VerifyUtils.isNotEmpty(vo.getOpUserId())) {
params.put("op_user_id",vo.getOpUserId());
}
if (VerifyUtils.isNotEmpty(vo.getRefundAccount())) {
params.put("refund_account",vo.getRefundAccount());
}
return params;
}
}
http执行的方法
public static String executeBySslPost(String url, String body,String certificatePath,String password) throws Exception {
String result = "";
//商户id
//指定读取证书格式为PKCS12
KeyStore keyStore = KeyStore.getInstance("PKCS12");
//读取本机存放的PKCS12证书文件
FileInputStream instream = new FileInputStream(new File(certificatePath));
try {
//指定PKCS12的密码(商户ID)
keyStore.load(instream, password.toCharArray());
} finally {
instream.close();
}
SSLContext sslcontext = SSLContexts.custom().loadKeyMaterial(keyStore, password.toCharArray()).build();
//指定TLS版本
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext, new String[]{"TLSv1"}, null, SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);
//设置httpclient的SSLSocketFactory
CloseableHttpClient httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();
try {
HttpPost httppost = new HttpPost(url);
StringEntity reqEntity = new StringEntity(body, "UTF-8");
httppost.setEntity(reqEntity);
System.out.println("Executing request: " + httppost.getRequestLine());
CloseableHttpResponse response = null;
try {
response = httpclient.execute(httppost);
result = EntityUtils.toString(response.getEntity(),"UTF-8");
} catch (Exception e) {
e.printStackTrace();
log.error("请求失败", e);
throw new RuntimeException(e);
} finally {
try {
response.close();
} catch (IOException e) {
e.printStackTrace();
}
}
} catch (Exception e) {
e.printStackTrace();
log.error("请求失败", e);
throw new RuntimeException(e);
} finally {
try {
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return result;
}
最终的返回结果
System.out.println(JSON.toJSONString(result,true));
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